Quadratic recursive convolution (QRC) in dispersive media simulation of finite-difference time-domain (FDTD)

Abstract

This paper presents a novel formulation for dispersive media computation in finite-difference time-domain (FDTD). Motivated by conventional recursive convolution (RC) methods in handling convolution integral, the method name quadratic RC (QRC) makes improvement in the approximation of electric field in convolution integral. The electric field is approximated by quadratic function determined by the fields at three time steps at current, next and former. Via quadratic interpolation, the convolution integral result is approximated by the linear combination of three electric fields, rather than two fields in trapezoidal RC (TRC) or piecewise linear RC (PLRC) and one field in constant RC (CRC). Because three electric fields is required for the convolution integral, the method needs two more back level storage of the electric fields to fulfill the recursion process. Numerical demonstrations of Debye and Drude slab's transmission and reflection coefficients demonstrate the efficiency and accuracy of the novel method.

Experimental demonstration of invisible electromagnetic impedance matching cylindrical transformation optics cloak shell

“…In order to get all of the unit geometric sizes shown in figures 4(c) and (d) with predefined property values indicated by equation (2) with specified a and b, the effective material property extraction uses software generated scattering parameters obtained by Microwave Studio in CST software. Then, the standard S parameter retrieval method is performed to obtain the required structure with effective material properties, in which refractive index n and impedance z could be retrieved through [7,31,32]: Then, the corresponding electric permittivity and magnetic permeability could be calculated by…”

“…Transformation optics (TO) manipulate waves in a manner of spatial alternation, which makes the wave flow bypass the cloaking object, rather than absorb it. Electromagnetic cloak metamaterial structures realize omnidirectional minimized electromagnetic disturbances in this way [1][2][3][4][5][6][7][8]. This unique property breaks the traditional understanding about the interaction between an object and electromagnetic wave, creating a different hiding method besides the electromagnetic absorbing structure and material, and thus becoming an interesting direction since then [9][10][11][12][13][14][15][16][17][18].…”

Reflection modulation generated by scale-free network resonator periodic structure

“…The metamaterial units are arranged in regular two-or three-dimensional periodical arrays or in random positions [12,[14][15][16][17]. They all have a common point: every unit only generates interaction with the adjacent units [13,[18][19][20][21][22][23]. Electromagnetic frequency selective surface, which mainly relies on resonance, could reflect or transmit electromagnetic wave in nearly unity ratio, and partial reflection at resonance frequency is rare to see with this type of thin surface consisted of lossless materials.…”

Blocking gate resonator rasorber surface brings wide band electromagnetic absorption performance approaching theoretical limit

“…Many studies have been carried out to realize broadband absorbing and lightweight absorbers . While designing a thin absorber with a wideband frequency response is still a challenging, because theoretical bound of bandwidth and thickness is usually hard to reach . Rasorber structure which combines characteristics of radome and absorber is applied in designing high‐performance radome structure with absorbing bands .…”